I’m a new seller and only have a few items, so here’s what works for me on a PC with Windows 7:
Open the PDF you downloaded from Seller Central. Click "Edit’ (second tab over up on the toolbar) then scroll down to ‘take a snapshot’.
Then highlight the label you want to print leaving about 1/4" whitespace all around, then right click the highlighted area and click ‘print’
The print dialog box will open and up top left select the Dymo LabelWriet 4XL. On the bottom left click ‘Page Setup’. Under ‘Size’ choose 30334. The rest of the settings should be fine so click ‘OK’.
The preview window (lower right) should now show the correct size label (2.25" x 1.25"). Go back up to the top left and change the number of copies to 2 or 3 (just as a test), then click ‘Print’. If all goes well, go back and change the number of copies to the number of labels you need.
Hopes this works for you. Figuring out how to get the labels to print was beyond aggravating.
PS - I can’t take all the credit for coming up with this . Someone on page 1 of this thread ( Hamster Roll ) made mention of the snapshot method but his post was a bit vague.